// PUT api/Comment/5
        public HttpResponseMessage PutComment(int id, Comment comment)
        {
            if (!ModelState.IsValid)
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }

            if (id != comment.CommentID)
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest);
            }

            db.Entry(comment).State = EntityState.Modified;

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException ex)
            {
                return Request.CreateErrorResponse(HttpStatusCode.NotFound, ex);
            }

            return Request.CreateResponse(HttpStatusCode.OK);
        }
        // POST api/Comment
        public HttpResponseMessage PostComment(Comment comment)
        {
            if (ModelState.IsValid)
            {
                db.Comments.Add(comment);
                db.SaveChanges();

                HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, comment);
                response.Headers.Location = new Uri(Url.Link("DefaultApi", new { id = comment.CommentID }));
                return response;
            }
            else
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }
        }